Help Needed for AK 105 Conversion

[The Paper Pimp]

howdy folks, i'm in the process of having my sgl converted to an AK 105 clone by a professional gunsmith (i know, i know, it would be so much cheaper if i did it myself or if i went with a builder on here but the truth is that i've been to a BP and have done a 1:1 build in someone's garage and wasn't satisfied with the outcome, i even asked said builder if he would schedule me for another 1:1 session and I was completely ignored, eh, he charged too much anyway).

so my question/inquiry is related to the gas block. i have both a Bulgarian FSB/GB and a Russian FSB/GB (if anyone's thinking about doing a 105 clone know that those two parts are very difficult to find, especially the Russian FSB/GB and the correct Russian 500m rear sight (holy hell, took me over a year to source those 2 parts).

anyway, from what i understand the Russian FSB sits back from the gas port so my barrel would have to be turned, welded shut and redrilled while none of this would happen if the Bulgy FSB is attached.

is having a barrel with its original gas port welded shut and redrilled for a Russian FSB a safe thing to do or would the welded gas port fail over time?
i really don't want to ruin a Russian barrel.

[The Paper Pimp]

and here I thought that the "AK Team" could help

[96chevjumps]

I will say it would fail but only after a long long time. The welder would have to try to get as deep as possible without entering the bore to get it to last. As long as it was welded past the ports circumference and then turned down to its correct diameter it would help any thin spots that would crack out over time.

[The Paper Pimp]

thank you 96chevjumps for the response.

[SVT-40]

I've built AK-105's using both the Bulgarian as well as the Russian FSB /GB....Both had Bulgarian made barrels. The Rifle with the Bulgarian FSB /GB is in the pic below...It was a pretty simple build, as it did not need any modifications to get the FSB /GB to line up with the gas port in the barrel...



The Russian FSB /GB is about 3mm shorter back to front than the Bulgarian. In the pic below the Russian unit is installed on the barrel another Bulgarian unit is placed above it for comparison.


The main difference between the two units is the length of the gas tube "receptacle" for some reason the Bulgarians made theirs a bit longer... So the gas port on their barrels is 3mm or so farther forward...



My solution was to modify the port INSIDE the Russian FSB / GB to accommodate the gas port already existing in the Bulgarian barrel. The FSB /GB is very beefy in this area and can easily accommodate the modifications.

In the pic below you can get an idea as to what I did.



The only "issue" using the Russian unit on the Bulgarian barrel is when installed the barrel will protrude about 3mm out from the front of the FSB /GB, as seen in the pic below.Yeah I know the barrel protrudes from the FSB / GB... But since it will be covered by the muzzle booster or barrel extension who cares. No need to mess with that, and possibly damage the crown or allow the high velocity gasses exiting the muzzle to mess with a modified crown....

Additionally the barrel has to be turned down slightly in the area behind the gas port so the FSB / GB can slide on to that area... Not a big deal at all, and can be accomplished using a file and sand paper.



Barrel all populated and ready for installation on it's receiver!!! In the pic I had not yet pinned anything in case there was a need to slightly move any component.



I hope this helps you!!!

[Centaine]

I've built AK-105's using both the Bulgarian as well as the Russian FSB /GB....Both had Bulgarian made barrels. The Rifle with the Bulgarian FSB /GB is in the pic below...It was a pretty simple build, as it did not need any modifications to get the FSB /GB to line up with the gas port in the barrel...

nice 104, is it 545 or 762? kinda looks like 545 from the mag..

[The Paper Pimp]

104 is 762
105 is 545...both pictured


SVT, thank you for the detailed response. PM sent.

[Centaine]

Thanks^ wasnt sure.

[SVT-40]

The completed rifle above is a AK-105 in 5.45, as is the barrel unit in the above pic's.

Here are a few pic's of the 7.62 AK-104 I built. Not painted at that point...

[Centaine]

theres so many variants out there its unreal.

[The Paper Pimp]

no problem. they look similar, the main give away is the magazine.

[Centaine]

no problem. they look similar, the main give away is the magazine.

yea that was what threw me off.. lol I was like that dont look like 762.

[The Paper Pimp]

there's a 3rd variant in 5.56

[SVT-40]

there's a 3rd variant in 5.56

They call the 5.56 AK-102

Yup... the only issue is there are no 5.56 parts kits to use as a base to make a rifle from... The only real source would be to use a SAIGA rifle as your base, and replace the front end with a Bulgarian barrel unit.......

[hellayella]

mine would be AK 105 barrel assembly and fixed stock AK74 kit (of course not kosher but I don't give a @#$%!